反应详情

Under a nitrogen atmosphere, slowly add 75 mmol of a 10% aqueous sodium hydroxide solution to a solution of 2 g (7.5 mmol) of ethyl 7-acetoxy-2,3-dihydro-1,4-benzodioxin-2-carboxylate in 20 cm3 of methanol. Stir at room temperature for 6 hours and then, after concentrating under reduced pressure, acidify the mixture with a 2N hydrochloric acid solution. Extract with diethyl ether the acid which precipitates, then, after drying and concentration to dryness, wash the resulting acid with methylene chloride. 7-Hydroxy-2,3-dihydro-1,4-benzodioxin-2-carboxylic acid is thereby obtained in a yield of 85%. Melting point: 204° C. ##STR48##

1. concentrationafter concentrating under reduced pressure
2. extractionExtract with diethyl ether the acid which
3. customprecipitates
4. customafter drying
5. concentrationconcentration to dryness
6. washwash the resulting acid with methylene chloride